61521 has 4 divisors (see below), whose sum is σ = 82032. Its totient is φ = 41012.

The previous prime is 61519. The next prime is 61543. The reversal of 61521 is 12516.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61521 - 2¹ = 61519 is a prime.

It is a D-number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 61521.

It is not an unprimeable number, because it can be changed into a prime (61511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10251 + ... + 10256.

It is an arithmetic number, because the mean of its divisors is an integer number (20508).

2⁶¹⁵²¹ is an apocalyptic number.

It is an amenable number.

61521 is a deficient number, since it is larger than the sum of its proper divisors (20511).

61521 is a wasteful number, since it uses less digits than its factorization.

61521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20510.

The product of its digits is 60, while the sum is 15.

The square root of 61521 is about 248.0342718255. The cubic root of 61521 is about 39.4767261282.

It can be divided in two parts, 615 and 21, that added together give a palindrome (636).

The spelling of 61521 in words is "sixty-one thousand, five hundred twenty-one".